usb: xhci: improve error message for targetless transfer event

usb: xhci: improve error message for targetless transfer event

Improve error message for unknown transfer event without a TRB, by also
printing the event code number. This removes the inevitable question;
"what was the unknown event code exactly?"

Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240626124835.1023046-13-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>